Holmium-166 Radioembolization in Hepatocellular Carcinoma: Feasibility and Safety of a New Treatment Option in Clinical Practice

Purpose To investigate clinical feasibility, technical success and toxicity of 166 Ho-radioembolization ( 166 Ho-RE) as new approach for treatment of hepatocellular carcinomas (HCC) and to assess postinterventional calculation of exact dosimetry through quantitative analysis of MR images. Materials and Methods From March 2017 to April 2018, nine patients suffering from HCC were treated with 166 Ho-RE. To calculate mean doses on healthy liver/tumor tissue, MR was performed within the first day after treatment. For evaluation of hepatotoxicity and to rule out radioembolization-induced liver disease (REILD), the Model for End-Stage Liver Disease (MELD) Score, the Common Terminology Criteria for Adverse Events and specific laboratory parameters were used 1-day pre- and posttreatment and after 60 days. After 6 months, MR/CT follow-up was performed. Results In five patients the right liver lobe, in one patient the left liver lobe and in three patients both liver lobes were treated. Median administered activity was 3.7 GBq (range 1.7–5.9 GBq). Median dose on healthy liver tissue was 41 Gy (21–55 Gy) and on tumor tissue 112 Gy (61–172 Gy). Four patients suffered from mild postradioembolization syndrome. No significant differences in median MELD-Score were observed pre-, posttherapeutic and 60 days after 166 Ho-RE. No deterioration of liver function and no indicators of REILD were observed. One patient showed a complete response, four a partial response, three a stable disease and one a progressive disease at the 6 months follow-up. Conclusion 166 Ho-RE seems to be a feasible and safe treatment option with no significant hepatotoxicity for treatment of HCC.